DETROIT — Most Buick vehicles sold in the United States after 2016 could be imported from China and Europe, according to two sources familiar with parent General Motors Co.’s plans.

Only two of Buick’s future US models, replacements for the mid-size LaCrosse sedan and the large Enclave crossover, are expected to be built in North America, according to the sources, who did not want to be identified because their companies work with GM.

The increasing tendency of US carmakers, including Ford Motor Co., to shift more vehicle production to plants outside the United States is a hot-button topic in current contract talks with the United Auto Workers.

“We do not comment on future product speculation,” a Buick spokesman said Tuesday.

Buick is planning to shift production of the compact Verano sedan from Michigan to China in late 2016, the sources said. Production of the mid-size Regal sedan is likely to shift from Canada to either China or Europe in 2017, they added.

Buick is also planning to add two new US models from overseas plants: the compact Cascada convertible, which will be imported early next year from Europe, and the compact Envision crossover, which will be imported from China in late 2016.

News of the US arrival of the Buick Envision, which went into production last year in China, was reported Monday by Automotive News. Buick unveiled the Cascada earlier this year at the Detroit auto show.

The subcompact Encore crossover is currently imported from Korea. Production is eventually expected to shift to China, the sources said.

In Detroit, Cindy Estrada, head of the United Auto Workers’ GM department, said the automaker would be “tone deaf” to import vehicles from overseas “after the sacrifices by US taxpayers,” as well as union concessions, to create a profitable GM after a government-funded bailout in 2009.

The LaCrosse is being redesigned next spring, with production moving to Hamtramck outside Detroit.

The Enclave is slated to be redesigned in early 2017. Production is expected to remain in Lansing, Michigan.

China is the largest market for the Buick brand, with sales last year of 919,582 vehicles, more than four times the 228,963 vehicles that Buick sold in the United States.